Give an example of a law that implements an ethical principle. Give an example of a law that enforces a particular group's idea of how people should behave?

There is very little connection between law and ethics. Ethics precedes law in the sense that ethical principles help determine whether or not we should pass specific laws. There are many examples of laws that implements an ethical principle; murder, theft, assault, rape, robbery, fraud, etc. These laws enforce ethical rules.  Every individual is responsible for following these laws through ethical standpoints because they enforce ethical rules. There are other laws that implement ethical principle as well under different circumstances. One example would be the copyright law. This law gives a right to your own property and prohibits anyone from stealing it from you.

The many examples of laws that enforces a particular group's idea of how people should behave are all around us. There are those that do things that others are just not going to approve of no matter what.  One prime example would be gay marriage. There are those who choose to live their lives in a relationship with the same sex and then there are those who completely disapprove of this. Although this is America where we have the freedom to live our lives however we want, there are laws in some states that are against gay marriages. There are other laws that enforces a particular group's idea of how people should behave which include the laws that are against drug and alcohol use. Even though drugs are illegal there those who use them. Then there are laws against alcohol use like the limitations on the use of alcohol.

References

Baase, S. (2008). A gift of fire: Social, legal, and ethical issues for computing and the Internet (3rd ed.). Upper Saddle River, NJ: Pearson.